Decimal matrix adder utilizing gas discharge tubes



May 5, 1970 R. F. POND 3, 8

DECIMAL MATRIX ADDER UTILIZING GAS DISCHARGE TUBES Filed Feb. 9. 1967 2 Sheets-Sheet J.

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O K I n O l! r N mmmmssz lllllallmmwmibz x llllill' INVENTOR. RICHARD F. POND ATTORNEYS United States Patent 3,510,638 DECIMAL MATRIX ADDER UTILIZING GAS DISCHARGE TUBES Richard F. Pond, 7802 Newman St., Huntington Beach, Calif. 92647 Filed Feb. 9, 1967, Ser. No. 614,964 Int. Cl. G06f 7/48; H03k 17/52 US. Cl. 235-168 4 Claims ABSTRACT OF THE DISCLOSURE An adding machine wherein gas discharge tubes, such as neon tubes, having at least two pairs of electrodes per tube serve as switching elements in the adder circuit. A third pair of electrodes in the gas discharge tube may serve as the tens carry-over mechanism.

BACKGROUND OF THE INVENTION Field of the invention Adding machine or calculator utilizing gas discharge tubes as independent switching means.

Description of the prior art Although gas discharge tubes have been suggested in the past for use in calculators, the known circuits have employed tubes essentially having three elements so that one element is common to two circuits. The present invention utilizes gas discharge tubes having at least two pairs of electrodes in each tube, there normally being no electric connection between the pairs of electrodes.

SUMMARY OF THE INVENTION The present invention uses gas discharge tubes with at least two completely independent pairs of electrodes so that there is no undesirable intercoupling between circuits.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a semi-diagrammatic illustration of a gas discharge tube suitable for use in conjunction with the present invention.

FIG. 2 is a schematic diagram of a x 10 grid circuit suitable for use in the present calculator but omitting the readout circuits and tens carry-over circuits.

FIG. 3 is a schematic diagram of a suitable readout circuit.

FIG. 4 is a schematic diagram of a ten carry-over circuit for carrying a digit from one tens grid to the next.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, there is shown a gas discharge tube suitable for use in conjunction with the present invention. The tube includes an envelope 20 of glass, the envelope being filled with a noble gas, typically neon or argon, which is capable of ionizing and conducting electricity when subjected to a sufiiciently high voltage. Included are a first pair of electrodes designated 22 and 24 and, as will be later seen, these particular electrodes are used as a switching element, i.e. these electrodes have the ionization voltage applied thereto rendering the tube conductive. Although the electrodes 22 and 24 are shown entering the tube at right angles to each other, this is only for ease of illustration and they might be side by side as are the other electrodes described. A second pair of electrodes designated 26 and 28 serve to operate a readout circuit. Thus, referring to FIG. 3 electrodes 26 and 28 are connected to a relatively low voltage battery 30 and a light bulb 32. The battery 30 is of such a low voltage that it is incapable of causing Patented May 5, 1970 or maintaining ionization within the tube 20. However, if one now applies an ionizing voltage between the electrodes 22 and 24, the gas within the tube becomes conductive so that current can also flow between the electrodes 26 and 28, causing the readout bulb 32 to light.

In addition, the tubes can contain a third pair of electrodes designated 34 and 36 and these electrodes are used to actuate a tens carry-over mechanism. Thus, referring to FIG. 4, the electrodes 34 and 36, if used for a carry function, as is later described, will carry a digit over into the next adjoining decimal grid when the answer achieved in the first grid, or any preceeding grid, is ten or above.

In FIG. 2, of the tubes 20 are arranged in a square grid there being ten X columns and ten Y rows of tubes interconnected as shown. A plurality of switches as at 38 lead to each of the X columns and have numbers thereon designated zero through nine all of the switches leading to a common source of an ionization voltage 40. Similarly, ten switches as the switch 42 are arranged in the Y rows leading to a common ground 44. Above each of the tubes 20 are a pair of electrodes leading to the appropriate readout number (abbreviated R0 in the drawing) and a second set of electrodes which may lead to a tens carry-over circuit in the next grid. In the drawing, the symbol C has been used to indicate that there is a carry-over while the symbol C has been used to indicate that there is no carry-over.

To take an example, if one pressed the five switch on the X axis and the three switch on the Y axis the tube designated 46, and no other, would ionize resulting in a current flow between the readout electrodes which, as is shown, would readout on a board designated 8. Since the sum of 5 and 3 is a single digit with no carry-over, it will be noted that there is no carry-over to the next column, i.e. the symbol 6 appears. Although all of the tubes have been shown with six electrodes, since it is normally simpler to make all of the tubes the same, it will be obvious that those tubes wherein there is no carry-over, such as the tube 46 just described might have four electrodes therein rather than six.

To take another example, if the switch 5 on the X axis and the switch 6 on the Y axis were depressed, the sum would be 11 so that there is a readout of 1 and the carryover circuit is actuated and there would be a ones carryover to the next decimal place.

It will be obvious, that for a given calculator, one needs one of the above described grids for each decimal place. Thus for a ten decimal place instrument, one would use ten of the grids described above with the appropriate carry-over circuitry. It is obvious that it is only in the units grid circuit that the answer is read out directly as is shown in FIG. 3. From the tens grid on, the readout must go through the carry circuit first to see if there is a carryover from the previous column.

Although a specific embodiment of the invention has been described, it will be obvious to those skilled in the art that many variations can be made without departing from the spirit of this invention.

I claim:

1. A calculator comprising in combination:

(a) a square grid of independent gas discharge tubes;

(b) each of said tubes having at least first and second pairs of electrodes therein, said pairs being normally insulated from each other;

(c) a series of X axis switches;

(d) a series of Y axis switches;

(e) a voltage source sufficient to ionize one of said gas discharge tubes said voltage source having two terminals;

(f) interconnections between said voltage source, said switches and a first pair of electrodes within each of said tubes each of said interconnections leading trom one terminal of the voltage source through an X axis switch to one electrode and leading from the other terminal of the voltage source through a Y axis switch to the other electrode of said first pair of electrodes; whereby closing one X axis switch and one Y axis switch will cause one of said tubes to ionize; and

(g) a readout circuit connected to said second pair of electrodes in each of said tubes.

2. The structure of claim 1 wherein neon tubes are employed as gas discharge tubes.

3. The structure of claim 1 wherein there are 100 gas discharge tubes arranged in a square array with 10 X axis and 10 Y axis switches.

4. The structure of claim 1 wherein at least some of the gas discharge tubes include three independent pairs of electrodes, namely a first pair connected to the X and Y axis switches and adapted to cause the tube to ionize and become conductive, a second pair connected to a readout circuit said first and second pairs being as defined in 3,069,086 12/1962 Papo 235-1 6 8 X 2,907,520 10/1959 Stott et al 235-473 X 2,872,108 2/1959 Koehler 235173 OTHER REFERENCES Yaohan Chu: Digital Computer Design Fundamentals, 1962, pp. 357-8.

1. Tai: Core Matrix Subtraction System, IBM Technical Disclosure Bulletin, October 1959, pp. 15-16.

EUGENE G. BOTZ, Primary Examiner D. H. MALZAHN, Assistant Examiner US. Cl. X.-R. 235l73, 176 

